1. Field of the Invention
The present invention relates to a serine/threonine kinase, a DNA coding for said kinase, a recombinant vector comprising said DNA, a transformant transformed with said vector, and a process for preparing the serine/threonine kinase.
2. Prior Art
Various signals from the exterior of a cell are transmitted through receptors on the cell surface into the cell and ultimately into the necleus. The signals transmitted into the nucleus activate transcription factors and, as a result, expression of a group of genes is induced or repressed to produce phenotypes such as cell proliferation, differentiation and cell death. Many transcription factors have been cloned and the structure of functional domains have been elucidated: MOLECULAR BIOLOGY OF THE CELL THIRD EDITION, pp. 401-469. These functional domains are known to include leucine zipper, helix-loop-helix and zinc finger structures. Among them, the leucine zipper structure is a motif commonly found in such transcription factors as Jun/Fos, ATF/CREB and C/EBP families and these transcription factors form homo- or hetero-dimers through their leucine zipper structures to control the transcription of specific genes: Hai, T. et al., Proc. Natl. Acad. Sci., USA, 88:3720-3724 (1991).
Recently, it is reported that the leucine zipper structure is also found other functional molecules than the transcription factors (Holzman, L. B. et al., J. Biol. Chem., 269:30808-30817, 1994), suggesting that the leucine zipper structure not only facilitates the binding between transcription factors but also acts generally as a protein-protein interactional domain in cells.
Therefore, identification of molecules interacting with the leucine zipper domain is considered to be useful in analyzing not only new functions of transcription factors but also functions of the leucine zipper structure in other molecules than the transcription factors.